Process of electrical separation of conductors from non-conductors.



No. 668,79l. Patented Feb; 26,- lam.

, L. l. BLAKE & L. N. monscuan. PROCESS OF ELECTRICAL SEPARATION 0F CONDUCTORS FROM NDN-CDNDUGTOBS.

(Application filed Mar. 1.6, 1898.) N o M o d e l v NVENTORS M2143; \j}mm W. ame 7 Jfu 4Vd.

A ATTORNEY.

WITNESSES:

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UNrTED STATES PATENT LUCIEN l. BLAKE, OF LAWRENCE, AND LAWRENCE N.MORSCHER, OF NEODESHA, KANSAS.

PROCESS OF ELECTRICAL SEPARATION OF CONDUCTORS FROM NON-CONDUCTORS.

SPECIFICATION forming part of Letters Patent No. 668,791, dated February26, 1901.

Application filed March 16, 1899. Serial No. 709,238. (No specimens.)

To (6 IU/I/OYTI/ it may concern:

Be it known that We, LUCIEN I. BLAKE, of Lawrence,county of Douglas, andLAWRENCE N. MORsoHER, of Neodesha, county of Wilson, State of Kansas,citizens of the United States, have invented a certain new and usefulImprovement in Processes of Electrical Separation of Conductors fromNon-Conductors, of which the following is a specification, referencebeing had to the drawing accompanying and forming a part of the same.

The process relates generally to the art of separating particles orgrains having avarying or different electrical conductivitythat is, theseparation of conductors (or those known as relatively good conductors)from non-conductors (or those having relatively poor electricconductivity.)

Animportant application of the principle of the invention, as describedand set forth herein, is in the separation of particles of precious orother metals and their compounds from sand, silica, slate, or othersimilar material occurring with metals in a state of natu re and also inthe recovery of metals or their compounds occurring in waste mixturessuch, for example, as result from various processes of ore reduction.

The principle of the invention is based upon the facts, (which we havefully and practically proved,) first, that when a mass or mixture ofconducting and non-conducting particles or grains is brought into anelectrostatic field or is charged directly the conductors acquire theirinductive or direct charges instantly, While the non-conductors requirean appreciable time to become charged; second, that conductors of onepotential when brought into contact with conducting-surfaces ofdifferent or opposite potential instantly acquire the same potential asthe conducting-surface and are repelled therefrom, while thenon-conductors require an appreciable time of contact with such surfacebefore acquiring the same potential as said surface and being repelled.It is evident that the greater the difierence in potential between themixed mass and the conducting-surface the more marked will be therepelling action and that if the potentials are of opposite sign theaction will be still more marked.

Our invention consists, in general terms, of submitting a mass ormixture of conducting and of non-conducting particles or grains to theaction of an electrostatic field or charge of one potential and thensubmitting the mass to the action of an electrostatic field or charge ofanother or op, osite potential, whereby the conductors qui%kly acquirethe same potential as the surface communicating the final electrostaticcharge and are quickly repelled therefrom, while. the non-conductingparticles acquire the same potential as the conducting-surface so slowlythat they pass off at the bottom of the surface before any repellingaction takes place. Thus the separating action is due to the differenceof time required for the conducting particles and for the non conductingparticles, respectively, to acquire the same potential as the finalcharging-surface.

Referring to the drawing, the view shown illustrates a section of oneform of mechanism designed to practice our process.

Ais a flexible belt of electric conducting material driven in any properway, as by the rolls B and G, and upon whichis deposited through thehopper D-the mixture or mass to be operated upon-such, for example, asgranular metal mixed with sand or similar non-conducting granularparticles.

. E is a metallic plate or conducting-surface of suitable size and shapeextending parallel to and positioned above the bolt A, which plate isconnected to a source of electrostatic potential F. The space betweenthis plate and the belt A is such as to insure that the mixture beingcharged by the plate will not be lifted from the belt by electricalattraction.

G is a smooth plate or conducting-surface inclined downwardly frombeneath the roll B. This plate in one use of the apparatus is to remainelectrically neutral or in electrical connection with a ground.

H is a metallic plate or conducting-surface positioned opposite theplate G and at a distance, practically as is shown by the drawings, andthis plate is connected to a source of electrostatic potential I ofopposite sign to that of F. J is another metallic plate arranged belowthe plate G and sustaining a potential from a source of electricity K ofsign opposite that of I. i

The mixture of conducting and non-conducting grains or particles isdropped upon the belt and carried in a sheet or stream of practicallyuniform thickness along under the plate E at a speed sufficient toinsure that the mass, especially the non-conducting particles thereof,will receive its full inductive charge before it falls from the beltthatis, a charge of sign opposite that of F. As the mixture falls from thebelt it drops through the field produced by the plate H, and as theconducting-plate G is charged by induction from H to the opposite signfrom that of the falling mixture upon impact of the mixture on G theconducting particles instantly lose their induced charges obtained whileon the belt and instantly receive opposite charges by contact with G,and so are promptly repelled from G, being also attracted by H in thegeneral direction indicated by the arrow L. The poorer conductingmaterials, however, not having time during their fall along the plate Gto give up their charges to the plate or to receive a new charge from Gor a charge due to H, are held by attraction to the plate G, and thusglide along the same in the direction indicated by the arrow M, or inastream separate from that of the conducting partic] es. As thenon-conducting particles leave the plate G they are still farther guidedand maintained in a stream or by the action of the charged plate J.

A diaphragm or similar device N may be provided to further insure theseparation of the falling streams of conductors and nonconductors, andreceptacles O and P may be provided to receive the particles of suchstreams.

The plates H and J are not essential, although they assist considerablyin a practical machine. If these plates be eliminated, then it would bedesirable to attach the plate G to a source of electrical energy thesign of which would be the same as that of F.

It is evident that our process may be carried on with other forms ofapparatus than that here shown. In an application for Letters Patent,Serial No. 26,152, of 1900, filed August 7, 1900, pendingcontemporaneously with the present application, we have shown andclaimed several forms of suitable apparatus.

It is also evident that the conveying belt or surface may be directlyconnected with the source of electrical energy and the mass therebydirectly charged instead of by induction from the plate E, as shown inthe form of apparatus here illustrated. It is also evident that if therepellingplate be electrically charged at a diiferent potential fromthat acquired by the particles from the electrostatic field caused bythe earth the separation of the conducting from the non-conductingparticles when the mass is brought in contact with the repelling-platewould take place or tend to take place in the same manner as abovedescribed; but commerciallyit will be desirable to give the mixedmatters a first charge of opposite potential to that which it receivesfrom the repelling-plate.

We are aware that it has been proposed to separate the particles ofmasses such as herein indicated by exposing such masses to electrostaticfields of force with the purpose of separating the lighter particlesfrom the heavier; but in no case that we are aware of has the differencein electrical conductivity between different particles (and irrespectiveof relative weight or action of gravity) been availed of for the purposeof effecting their separation.

\Vhat is claimed as new is-- 1. The herein-described process ofeffecting the separation of the electric conducting particles of a massfrom the non-conducting particles of the same, which consists inelectrically charging the particles of such amass by submitting the sameto an electrostatic field or charge of one potential, and thensubjecting such mass to an electrostatic field or charge of oppositepotential, whereby the conducting and quickly-electrified particles arerepelled from the non-conducting particles of slow electrification.

2. The herein-described process of separating conducting particles froma mass of nonconducting particles, which consists in conducting a streamof the combined particles or grains through an electrostatic field ofone potential, and then through an electrostatic field of anotherpotential.

LUOIEN I. BLAKE. LAWRENCE N. MORSCI'IER.

Witnesses:

JOHN Y. H. NORTON, FRED A. CLARKE.

